This study was undertaken to assess the need and demand for orthodontic treatment among 12-14-year-old north Jordanian school children. In total, 1002 students randomly selected to represent five geographical areas of Irbid were examined. The examinations were carried out twice, first on the pupils in the school premises and then using study models taken from each student. The dental health (DHC) and aesthetic (AC) components of the Index of Orthodontic Treatment Need (IOTN) were used as an assessment measure of the need for orthodontic treatment. The demand for orthodontic treatment was measured by asking the students 'if it was necessary, would they like to have their teeth straightened by an orthodontist'. The results showed that approximately one-third (34 per cent) of the children examined had a definite need for orthodontic treatment. Within this group, 73.5 per cent were in need of orthodontic treatment according to the DHC, 23.5 per cent had both DHC and AC great need scores, and 3 per cent were in need according to the AC only. Severe contact point displacement of more than 4 mm was the most common occlusal feature in the definite treatment need group, followed by impeded eruption of teeth, hypoplasia of a single tooth and increased overjet of more than 6 mm but less than or equal to 9 mm. The demand for orthodontic treatment among the students was 49 per cent. Approximately half of them (54 per cent) had a definite need for orthodontic treatment. This study provides baseline data on the need and demand for orthodontic treatment among a Jordanian population, which is important for planning public orthodontic and dental services.